[Question] ModelBinding and consecutive integers

[joacar]

Hi,

I generate some models dynamically on the client-side and sends a request the a controller to "inflate" the editor template which is then appended the the DOM.

// Controller
public IActionResult Add(ICollection<Model> models)
{
return PartialView("EditorTemplates/Model.cshtml", models[0]);
}

After appending the resulted template (or one has been deleted) I need to ensure that all models are in consecutive order with respect to name and id html attributes.

Is there any way to manipulate the model binding to accept none-consecutive or perhaps just use another identifier. Perhaps this is more difficult since probbly both model binding and name/id generation is affected.

Thanks!

#5642

[frankabbruzzese]

Model binder is already able to handle not consecutive indexes. See http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx/

[joacar]

Thanks @frankabbruzzese I will look into that!

[joacar]

@frankabbruzzese Do you have an example to override the whole process? Ideally I would like to generate <input type="hidden" name="Index" value="@Guid.NewGuid()" /> so that I don't need to iterate all items prior to submission to ensure they are correct. If I add one item at a time they all get indexed with zero.

Perhaps something like

// Signature example (can't recall paramers exactly for existing)
public static IHtmlContent EditorFor<TModel>(..., Func<TModel, string> indexId)
{
 // Generates <input type="hidden" name="Index" value="@indexId()" />
}

// Usage
@for(var i = 0; i < Model.Items.Count; ++i)
{
@Html.EditorFor(_ => Model.Items[i], "Template", model => mode.Id or _ => Guid.NewGuid())
}

[frankabbruzzese]

You may use Guids! This is the best way to do it. I do the same!
Unlickily I have no simple example, since I use Asp.net coreMvc Control Toolkit that has abstractions to solve this and other problems. You may look at the sources of the grid, but the level of abstraction is very high since everything must work with all ViewModels and also with custom templates(ie partial views) provided by the user. The, code that actuallly do stuffs is contained in providers, so the relevant code for grid is here. and in the various default templates used by the grid.

[joacar]

Found it rather hard to find the pieces that are related :)

Hopefully I'll have time this weekend to put togheter extensions methods that sit ontop of existingEditorFor{Model} that can provide the user the ability to

1. Use Guid as identifier (Typically used in scenarions for adding new resources, e.g. contacts to a phone book)
2. Use unique identifer to TModel (Adding existing resources, e.g. images to a photo album)

[frankabbruzzese]

@joacar, the part of the code dealing with Guids is the ServerCrudController<T, T1, K>, since all grid operations of the server grid are performed through ajax with the help of descendants of this generic controller. Pay attention, there are 2 ways to create a new row one for the batch grid(the one you are interested in) where the guid is packaged like [guid here] and the immediate grid that uses guids in a completely different way.

[Eilon]

We are closing this issue because no further action is planned for this issue. If you still have any issues or questions, please log a new issue with any additional details that you have.